The short version of Enkephalinase fits in a sentence. The long version — which is the one that helps — is below.
Reviewed 2026-07-06. Anything still debated is marked as such rather than presented as settled.
Regulatory treatment varies by jurisdiction. In Russia the compound is a registered prescription product, while in the European Union and the United States it is generally handled as a research chemical without a marketing authorization. Suppliers therefore operate outside pharmaceutical oversight, and buyers rely on supplier documentation for purity and identity claims. Chain of custody and third-party testing are the main verification tools. Analysts note that the absence of a pharmacopoeial monograph for research-grade material limits standardization across vendors.
Purity assessment relies mainly on reverse-phase high-performance liquid chromatography with ultraviolet detection. Because the peptide lacks a strong chromophore, detection often uses backbone absorbance near 214 nm. Identity is confirmed by mass spectrometry, typically electrospray ionization or matrix-assisted laser desorption, comparing the measured mass against the expected value. Amino acid analysis can verify composition after acid hydrolysis. Diastereomer content and residual counterions are reported less often, although both can influence biological assays.
Lyophilized material is generally stable for extended periods when kept dry at or below minus twenty degrees Celsius. Working solutions are less stable, and common practice is to aliquot and freeze them so that repeated freeze-thaw cycles are avoided. Aqueous solutions are sensitive to pH extremes and to microbial growth, so short-term storage at refrigerator temperature is typical. Oxidation and hydrolysis are the principal degradation routes. Reconstitution with sterile water or a mild buffer is standard, and solutions should be protected from light.
Regulatory status differs sharply by region. Selank holds a Russian marketing authorization, where it is supplied mainly as nasal drops, while authorities elsewhere have not approved it for medical use. Material sold internationally is therefore usually labeled as a research chemical rather than a medicine. Peer-reviewed publications come predominantly from Russian laboratories, and sample sizes are generally small. Whether the compound produces comparable effects under independent, well-controlled replication remains an open question that the broader literature has not settled.
Selank is a synthetic heptapeptide developed in Russia as a structural analogue of tuftsin, a naturally occurring immunomodulatory tetrapeptide. Its sequence, Thr-Lys-Pro-Arg-Pro-Gly-Pro, keeps the tuftsin core at the N-terminus and appends a Pro-Gly-Pro tail. Researchers at the Institute of Molecular Genetics in Moscow synthesized the compound during the 1990s while searching for peptides with combined anxiolytic and immunomodulatory activity. The added tail was intended to resist enzymatic cleavage and prolong the molecule's presence in circulation.
The compound has a calculated molecular weight near 751.9 daltons and carries a net positive charge at physiological pH because of its arginine residue. It dissolves freely in water and in common aqueous buffers, and typically appears as a white or off-white lyophilized powder. The amide backbone makes the molecule susceptible to peptidases, which limits oral use and favors intranasal or parenteral routes. Nomenclature in the literature varies: the substance is also described by the sequence abbreviation TP-7 and by a Russian trade designation.
| Property | Value | Notes |
|---|---|---|
| Typical purity report | 95% or higher by HPLC | Area percentage at 214 nm |
| Identity confirmation | Mass spectrometry | Electrospray or MALDI |
| Powder storage | -20 C, desiccated | Protect from light |
| Solution storage | 2-8 C short term | Freeze aliquots for longer |
| Quality document | Certificate of analysis | States method and value |
The primary structure of Selank is Thr-Lys-Pro-Arg-Pro-Gly-Pro, corresponding to the molecular formula C33H57N11O9 and a monoisotopic mass of roughly 751.9 daltons. The N-terminal threonine and the arginine residue in the fourth position are shared with tuftsin, which carries the sequence Thr-Lys-Pro-Arg. The three additional residues at the C-terminus, Pro-Gly-Pro, extend the chain and are associated with greater resistance to enzymatic degradation. This extension also separates Selank from the shorter parent peptide.
Naming conventions place Selank in the same research family as Semax, another Russian-developed peptide investigated for cognitive effects. The two compounds share a lineage but differ in sequence and in the biological systems proposed as their targets. Semax descends from ACTH fragments, whereas Selank descends from tuftsin. Publications sometimes identify Selank by its full peptide sequence or by laboratory codes rather than one uniform trade name. Because replication outside Russia is limited, reports on its properties are best read alongside the study design and the purity of the material tested.
Selank is a synthetic heptapeptide developed in Russia during the 1990s. Researchers at the Institute of Molecular Genetics of the Russian Academy of Sciences designed it as a stabilized analog of tuftsin, a naturally occurring immunomodulatory tetrapeptide. The compound has been studied primarily for its reported anxiolytic and nootropic effects. It remains largely unknown in Western pharmacology and is not approved as a medicine by major regulators such as the FDA or the EMA.
Reported pharmacological effects center on reduced anxiety-like behavior in animal models and on measures of memory and learning. Proposed contributing mechanisms include modulation of GABAergic signaling, shifts in monoamine turnover, and changes in the activity of enzymes that degrade neuropeptides. Effects on the expression of genes linked to neuroplasticity have also been described. No single molecular target is widely accepted, and whether the behavioral findings arise from one pathway or several remains an open question.
Selank is a synthetic heptapeptide with the sequence Thr-Lys-Pro-Arg-Pro-Gly-Pro. It was designed as a stabilized analogue of tuftsin, a naturally occurring tetrapeptide fragment derived from the immunoglobulin heavy chain. The additional Pro-Gly-Pro segment at the carboxyl terminus is intended to slow enzymatic cleavage. The compound is usually described in the literature as a synthetic peptide with anxiolytic and cognitive-related activity, a label that reflects a research context rather than an approved therapeutic category.
Enzymatic stability motivates the extra three residues at the carboxyl end. Native tuftsin is cleaved quickly by circulating aminopeptidases and carboxypeptidases, which limits its duration of action and its usefulness as a tool compound. Extending the chain with proline-rich segments is a common design tactic because proline constrains the backbone and slows proteolysis. The same Pro-Gly-Pro motif appears in other Russian-developed peptides of the era. Whether the full seven-residue chain is required for activity, or whether it acts mainly as a prodrug releasing tuftsin, remains unresolved.
Selank is a synthetic heptapeptide with the sequence Thr-Lys-Pro-Arg-Pro-Gly-Pro. Its four N-terminal residues reproduce tuftsin, a tetrapeptide fragment of the immunoglobulin heavy chain, while the C-terminal Pro-Gly-Pro extension is a synthetic addition. The peptide has a molecular mass near 752 daltons and carries a net positive charge at physiological pH because of the arginine and lysine side chains. Published indexes list it under the name Selank and the sequence abbreviation TKPRPGP. Solid-phase peptide synthesis is the standard production route for research quantities.
Proposed mechanisms centre on modulation of the GABAergic system, with reports of altered expression of genes related to GABA-A receptor subunits and changed monoamine turnover. Some studies describe inhibition of enkephalinase, the enzyme that degrades endogenous enkephalins, which may prolong opioid peptide signalling. Effects on brain-derived neurotrophic factor and on cytokine expression have also been reported. These findings come largely from animal models and small human studies, and the precise primary target remains unresolved.
Published clinical evidence is limited. Most controlled trials were conducted in Russia, enrolled modest numbers of participants, and appeared in Russian-language journals, which restricts independent verification. Reported outcomes include lower anxiety scores, improved attention and memory measures, and changes in fatigue ratings. Reviews written in English note methodological limitations such as small samples and inconsistent endpoints. Whether the compound produces clinically meaningful benefit relative to established anxiolytics is therefore an open question rather than an established finding.
Selank is a synthetic heptapeptide with the sequence Thr-Lys-Pro-Arg-Pro-Gly-Pro. It was designed at the Institute of Molecular Genetics of the Russian Academy of Sciences as a structural analogue of tuftsin, a naturally occurring tetrapeptide fragment of the immunoglobulin heavy chain. The added Pro-Gly-Pro tail was intended to slow enzymatic degradation and extend biological activity. In Russia it is registered as an anxiolytic nasal preparation, while regulators elsewhere have not approved it for clinical use.
== Awards == Major Awards 1. Young Scientist Medal (1988), by the Indian Science Congress Association, India. 2. INSA Young Scientist Medal (1991), by the Indian National Science Academy, New Delhi. 3. CRSI Bronze Medal (2002), by the Chemical Research Society of India. 4. MRSI Medal (2007), by Material Research Society of India. 5. Shanti Swarup Bhatnagar Prize (2007), awarded by CSIR, Govt. India. 6. DAE Outstanding Researcher Award (2009), awarded by Dept. Atomic Energy, Govt. India. 7. Thomson Reuters Research Excellence-India Research Front Award (2009). 8. The Infosys Prize for Physical Sciences 2012 by Infosys Science Foundation. 9. Khwarizmi International Award 2012 by Iranian Organisation for Science and Technology. 10. Swadeshi Innovation Award 2012 by the Swadeshi Science Movement, Kerala. 11. Sri Vidyadhiraja Samskrithi Puraskaram 2013 by Panmana Ashram, Quilon, Kerala. 12. CRSI Silver Medal 2013 by Chemical Research Society of India. 13. TWAS Chemistry Prize 2013 by The World Academy of Sciences, Trieste, Italy. 14. ISAS National Award for Excellence in Science and Technology 2014 by Indian Society of Analytical Scientists. 15. CHEMTECH CEW Award 2015 for Leadership and Excellence in Research and Development. 16. J. C. Bose National Fellowship, 2015, DST, Govt. India. 17. Web of Science-India Research Excellence-Citation Award 2017 by Clarivate Analytics. 18. MRSI Distinguished Lectureship Award, 2019-20, by Materials Research Society of India. 19. Goyal Prize for Chemical Science, 2019, by Kurukshetra University. Other Honors 1.
== Synthesis == Most animals and plants are able to synthesize vitamin C through a sequence of enzyme-driven steps, which convert monosaccharides to vitamin C. Yeasts do not make l-ascorbic acid but rather its stereoisomer, erythorbic acid. In plants, synthesis is accomplished through the conversion of mannose or galactose to ascorbic acid. In animals, the starting material is glucose. In some species that synthesize ascorbate in the liver (including mammals and perching birds), the glucose is extracted from glycogen; ascorbate synthesis is a glycogenolysis-dependent process. In humans and in animals that cannot synthesize vitamin C, the enzyme l-gulonolactone oxidase (GULO), which catalyzes the last step in the biosynthesis, is highly mutated and non-functional.
If treated early, the progression of glaucoma may be slowed or even stopped. Regular eye examinations, especially if the person is over 40 or has a family history of glaucoma, are essential for early detection. Treatment typically includes prescription of eye drops, medication, laser treatment or surgery. The goal of these treatments is to decrease eye pressure. Glaucoma is a leading cause of blindness in African Americans, Hispanic Americans, and Asians. Its incidence rises with age, to more than eight percent of Americans over the age of eighty, and closed-angle glaucoma is more common in women.
=== Halides === In halides, berkelium assumes the oxidation states +3 and +4. The +3 state is the most stable, especially in solutions, while the tetravalent halides BkF4 and Cs2BkCl6 are only known in the solid phase. The coordination of berkelium atom in its trivalent fluoride and chloride is tricapped trigonal prismatic, with the coordination number of 9. In trivalent bromide, it is bicapped trigonal prismatic (coordination 8) or octahedral (coordination 6), and in the iodide it is octahedral.
Typically, chia seeds are small flattened ovoids measuring on average 2.1 mm × 1.3 mm × 0.8 mm (0.08 in × 0.05 in × 0.03 in), with an average weight of 1.3 mg per seed. They are mottle-colored with brown, gray, black, and white. The seeds are hygroscopic, absorbing up to 12 times their weight in liquid when soaked; they develop a mucilaginous coating that gives them a gel texture. Chia (or chian or chien) has mostly been identified as Salvia hispanica L. Other plants referred to as "chia" include "golden chia" (Salvia columbariae). The seeds of Salvia columbariae are also used for food.
Sources: en.wikipedia.org
==== Perissodactyl research ==== Tissier & Smith (2026) reconstruct the early evolutionary history of Perissodactyla on the basis of a new phylogenetic study, recovering purported horse relatives Hyracotherium and Pliolophus as not belonging to Hippomorpha, and reporting evidence of rapid dispersals of Pliolophus and Cardiolophus in the northern continents around the Paleocene–Eocene thermal maximum. New fossil material of Ancylotherium hennigi, providing new information on the anatomy of members of this species, is described from the Plio-Pleistocene strata from Laetoli (Tanzania) by Harrison & Kwekason (2026). Radović et al. (2026) identify dental remains of Tapirus arvernensis from the Pliocene strata from the Ridjake fossil site (Serbia). Sun et al. (2026) describe new fossil material of Tapirus sanyuanensis from the Pleistocene strata from Renzidong Cave (Anhui, China), providing information on changes in anatomy of members of this species during their ontogeny, as well as evidence of morphological differences between populations of this species from Renzidong Cave and from the Wushan Longgupo Site (Chongqing, China). Handa et al. (2026) describe rhinocerotid fossils from the Phra Phut sandpit (Thailand), interpreted as indicative of late Miocene age of the studied assemblage, and report evidence of similarity of composition of the studied assemblage and other late Miocene rhinocerotid assemblages from sandpits in Chaloem Phra Kiat District in Nakhon Ratchasima. Sanisidro & Gutiérrez-Marco (2026) describe fossil material of Brachydiceratherium sp.
Structures that are intraperitoneal are generally mobile, while those that are retroperitoneal are relatively fixed in their location. Some structures, such as the kidneys, are "primarily retroperitoneal", while others such as the majority of the duodenum, are "secondarily retroperitoneal", meaning that structure developed intraperitoneally but lost its mesentery and thus became retroperitoneal.
In terms of the diagnosis of Becker muscular dystrophy symptom development resembles that of Duchenne muscular dystrophy. A physical exam indicates a lack of pectoral and upper arm muscles, especially when the disease is unnoticed through the early teen years. Muscle wasting begins in the legs and pelvis, and then progresses to the muscles of the shoulders and neck. Calf muscle enlargement (pseudohypertrophy) is quite obvious. Among the exams/tests performed are:
The three substrates of this enzyme are trypanothione disulfide, reduced nicotinamide adenine dinucleotide phosphate (NADPH), and a proton. Its products are trypanothione and oxidised NADP+. This enzyme belongs to the family of oxidoreductases, specifically those acting on a sulfur group of donors with NAD+ or NADP+ as acceptor. The systematic name of this enzyme class is trypanothione:NADP+ oxidoreductase. Other names in common use include trypanothione reductase, and NADPH2:trypanothione oxidoreductase. It employs one cofactor, FAD. The X-ray crystal structures of trypanothione reductase enzymes from several trypanosomatids species have been solved, including those from Crithidia fasciculata, Leishmania infantum, Trypanosoma brucei and Trypanosoma cruzi. The structures reveal that trypanothione reductase forms homodimers in solution with each of the two individual subunits comprising an flavin adenine dinucleotide-binding domain, an NADPH-binding domain and an interface domain. Examples of trypanothione reductase inhibitors include 5-nitroimidazole, febrifugine, imipramine and benzoxaborole.
Sources: en.wikipedia.org
Purity is usually reported as an HPLC area percentage, most often measured at 214 nm. Identity is confirmed separately by mass spectrometry. A certificate of analysis should state both the method and the observed value.
Dry powder is kept frozen, desiccated, and shielded from light. Dissolved material is aliquoted and frozen to limit freeze-thaw cycles. Short-term refrigerated storage is common for working solutions.
Russia registers it as a prescription nasal product. Most other markets classify it as a research chemical with no approved medical use. Oversight of purity and labeling is consequently minimal in those markets.
Selank is a synthetic seven-amino-acid peptide modeled on tuftsin, a fragment of the immunoglobulin G heavy chain. It was designed in Russia to combine anxiolytic and immunomodulatory properties in one molecule.